Robot vision systems are becoming very important in the application of adaptive control of automated welding systems. A serious problem which these systems must overcome is the harshness of the welding environment. Optical equipment used in adaptive control of the welding process is at a high risk of being damaged or rendered useless because of the spatter of particles of molten metal which are projected outward for the welding arc, fumes from the welding process that can leave a sooty residue on optical lenses and heat from the arc that can distort optical equipment.
Methods of protecting optical equipment in environments of high temperature and flying particles are mentioned in U.S. Pat. Nos. 3,321,265 issued May 23, 1967 to Serge and Marcel Clave, and 3,310,356 issued Mar. 21, 1967 to Willy Borberg. These patents are examples of specific enclosures used to protect optical equipment. Another example is found in U.S. Pat. No. 4,450,339 issued May 22, 1984 to Nelson R. Corby, Jr. These patents do not provide for the projection of a light which is required of an active vision system. U.S. Pat. No. 4,497,996 issued Feb. 5, 1985 to Charles J. Libby, Jr. provides for the projection of light but is constructed in such a way that it would require frequent cleaning.